by Jeff Day
When a drain gets clogged, the problem is either somewhere in the pipes just below the drain or in the larger main drain that those pipes lead to. Since small lines are more likely to clog than larger ones, chances are good that the problem is in one of the small lines closest to the drain. If more than one drain is clogged, however, the problem may well be with the main drain.
Make Sure a Pipe Isn't Plugged
Before you turn your attention to the main drain, eliminate the obvious:
Plunge first. Use a sink plunger on a clogged sink or tub. Use a toilet plunger on a clogged toilet.
If the sink or tub has an overflow drain, fill the tub or sink until water covers the overflow drain before you plunge.
Snake next. If the plunger doesn’t work, use a snake, which is a metal tape or cable with a corkscrew-looking plug on the end. Use the tape variety on a sink, feeding it down the drain until you meet resistance, and then pushing and pulling to try to break whatever is there.
On a toilet, use a toilet auger, as described in How to Fix Common Toilet Problems.
Try the baking-soda-and-vinegar trick. If water hasn't backed up into the sink or tub, try this eco-friendly drain cleaner:
- Dump about a cup of baking soda (not baking powder) into the open drain.
- Pour about 2 cups of white vinegar into the drain. The mixture will bubble vigorously.
- Close the drain.
- While the bubbles loosen the clog, boil a large pot of water.
- Open the drain and pour the boiling water down the drain, taking care not to splash the hot water on yourself.
- After about 10 minutes, run hot water from the faucet into the drain, to wash away the loosened clog.
Chemicals as a last resort. Use commercial drain cleaners as a last resort; the caustic ingredients are hard on pipes and they don’t always work. And if you end up having to disassemble some drain lines, you risk getting caustic chemicals on yourself.
Clearing at the Cleanout
If, despite all plunging and auguring, the problem persists, the clog is likely to be in the main drain.
Find the cleanout. Access to the main drain is through a clean-out plug, which is a disk with a built-in, raised, square nut that you turn to remove the plug. Find the nearest cleanout that’s below the clogged drain. In newer houses, you’ll find a clean-out plug that's roughly 1-1/2 inches in diameter near each sink — often it's under the sink. If there are sharp turns in the plumbing, there are additional cleanouts, probably hidden in a closet. In older houses there may be only one 3- or 4- inch diameter clean-out plug somewhere in the basement.
Remove the clean-out plug. Get a bucket and be ready to stand back. If the clog is anywhere below the cleanout, wastewater is going to pour out of the cleanout when you remove the plug. To remove the plug, unscrew it with a wrench or large pliers.
Option 1: Snake the drain. Feed a snake into the cleanout until you meet some resistance and then pull the tape back to remove the clog. Repeat a few times to make sure you get the whole clog. Put the clean-out plug back on and run hot water through the drain to break up what’s left of the clog. If the water still runs slowly, plunge and, if necessary, snake again.
Option 2: Blow out the clog. Instead of a snake, you could use a tool called a blow bag. A blow bag is a heavy-duty rubber bladder that attaches to a garden hose. When you feed the bag into the drainpipe and turn on the water, the bladder inflates, sealing the pipe. The bag also shoots water into the pipe so that pressure builds, hopefully to a point that breaks the clog loose.
For best results, connect the garden hose to the drain valve on your hot water heater so that the water pushing against the clog is hot.
Follow the directions that come with the bag closely: you don’t want the bag to get stuck in the pipe. Blow bags develop enough pressure to crack a toilet, so use them only in pipes.
Try the House Trap
If you can’t remove the clog at the cleanout, look for a house trap in the basement. A house trap is a U-shaped section of pipe in the drain line with cleanout plugs above each leg of the U. Remove the plugs and snake out the trap. Then run the snake through the drain line on either side of the trap and remove any obstructions you meet. Put the clean-out plugs back in their openings.
If the drain is still clogged, tree roots or other obstructions may be blocking the line between the house and the sewer. Call a plumber.
Writer Jeff Day still wonders which of his children flushed a tennis ball down the toilet.